Electric receptacle



Apri125,1939. GEBL'INN 2,155,925

ELECTRIC RECEPTACLE Filed April so, 193s 5 'sheets-sheet 24 .A llNvEm-ol? 6220722 f5/w22 ATToRNEYs April 25, 1939. G. E. BLINN 2,155,925

ELECTRIC RECEPTACLE Filed April 30, 1958 5 Sheets-Sheet 3 ENTOR lNv Glen f? 57:'27

ATTORNEYS ,April 25, 1939.

' Filed 4April so, .1938

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G. E; BLINN ELECTRIC RECEPTACLE 5 Sheets-Sheet 4 INVENTQR 670.722 E 5&2???

ATTORNEYS A @MM-m April 25, 1939- v E. BLINN 2,155,925-

ELECTRIC RECEPTAGLE Filed April so, 1938 5 sheets-sheet 5 @prag MQ m? Patented Apr. 25, 1939 lJNl'lEl) STATES Pillar-Jair` oFFlcEJ,

' Glenn E. Bunn, Leppin, N..J. Application April so, 193s, serial No. 205,160

12 Claims.

This invention relates to electric receptacles, and more especiallyto the safety type in which Ait is diiiicult or impossible to make accidental contact with live parts of the receptacle.

Electric receptacles of this nature have heretofore been proposed, but-they included either the disadvantage of requiring a specialPtype of plug which could not he used with the ordinary nonsafety type of receptacle or else the disadvantage 10 that the insertion and removal of the plug could be eiected only in two stages, one of which involved a twisting mo'tion, with theresult that persons unfamiliar with such devices experienced diiliculty in using them. v

On. the other hand, the electric receptacle according to my invention is adapted to receive any standard plug having two or more connection prongs which may be inserted and removed'by simple pushing and pulling motions, as in the case of the common non-safety receptacle. Yet

this receptacle provides a door, or doors, eiectively closing the holes provided to receive the connection prongs of a. complementary plug, except :when at least two such prongs are simultaneously tion with a contact-spring or other live part thereof vwith the likely result shocks or burns.

To this end my invention provides at least one lock for each door, the locks being released by trips in the prong-receiving holes. The trips and locks are so related with respect to the holes and doors that the insertion of an object into only one hole will not open the door which closes that of suiering electric hole. `By "doors is meant the means which' serve effectively to close the holes whether they are individual to each hole or constructed as a 40 single unit.

Three adaptations of a preferred embodiment of the invention are described in the following specication, and are illustrated in the drawings ngnsatransversevlpwukenalongune.

Fig. 1 is a section; thus, 2 and Fig. 4 are in effect views of opposite ends of the receptacle;

Figs. 5 and 6 are sectional views which correspend to Figs. 1 and 3, respectively, taken after the receptacle has been turned 90 on its longitudinal axis, Fig. 5 being a longitudinal section taken along the line 5-5 of Fig. `2, and Fig. 6. being similar to Fig. 5, but having been taken after a two-prong attachmentplug has been inserted; and n Fig. 7 is an end-view of the shell formed to accommodate the receptacle mechanism. y

The remainingiigures will be referred to hereinafter in connection with the' other adaptations. Referring now to Figs. 1-7, inclusive, wherein like reference characters indicate the same parts, there is shown a containing shell l which preieralzily is of insulating material and4 shaped to.

conform to the outline of the receptacle mechanism. This mechanism includes the usual contact springs 5, 6, screwed or riveted to a supporting plate so as to be in alignment with'holes 3, 4 pierced through one end of the shell; In thedrawings this end is represented as a at plate-like portion 2. These holes and their re spective contact springs are spaced and proportioned to receive the .connection prongs, or blades, of the standard two-prong attachment plug, such as is shown at 23 in Fig. 3 and Fig. 6. The invention is, however, adapted to be applied to receptacles intended for use with plugs having more than tw'o'prongs, as will hereinafter be explained.

Under each of holes 3 and l is hinged a door, i or shutter 1; 8 which, when in the position shownv in Figs. 1, 2 and 5, effectively closes thehole at the bottom and prevents any object inserted in the hole from touching a contact spring or other livepart of the receptacle. This is true because both doors 1 and 8 are hinged on lpins i1 and i8, and neither .one can be swung on its hinge toward the center of the receptacle while either of dogs II and l2 is between them. However, as both prongs of an attachment plug 23 are inserted through holes 3 and l the releasing means or trips 8 and I0, one for each hole, are pressed down through angie of about swinging the attached dogs il and I2 away :from the cenvter and allowing the heels o! both doors to move toward each other, as shown 'in Figs. 3 and 6, into the space previously occupied bythe dogs.

Accordingly, prongs 2l and 2 6 of the attachmentv pug can then pass bythe .doors and engage the contact springs l and 8 in the usualmanner.

Upon withdrawal of the plug 23, doors 'I and 3 will be restored to their original position, closing the holes, by reason of the action of springs I3 and I4. These springs are anchored at one end to xed pins I9 and 20, and at the other end are secured to pins 2| and 22 passing through the slotted rear portions of dogs II and I2. 'Ihese springs, therefore, tend to urge the dogs toward the center and each other, and the dogs, in turn, press against the heels of the door members which are thereby returned to the closed position.

From the foregoing description it will be apparent that the insertion of an object into either of the holes 3 and 4 can at most move only one of the two dogs, but since each dog is eifective to lock both doors in closed position neither door will therebyl be released. Furthermore, it will be seen that in order to release and open either door. both dogs must be moved away from their locking position and that, to accomplish this, both releasing trips 9 and III must be pressed down a sufiicient distance, as by the simultaneous be connected to the attachment ,plug 23 would insertion of both prongs of a standard attachment plug.

In the above-described adaptation, as well as in the other adaptations hereinafter described, the receptacle is illustrated inthe form known as a separable connector, suitable, for example, to connect the ends of flexible extension cords. End cap 24 is therefore provided to cover the terminal screws I5 and I6 to which may be attached the wires of a flexible cord passing through hole 35. The exible cord which would pass through a corresponding hole (not shown) in the plug. Screws 29 and 3l) serve to attach cap 24 to the body of shell I, and fscrews 21' and 28 secure the receptacle mechanism in the shell I. However, such details are shown merely by way of example, since any desired fastening means can be employed, arid the receptacle mechanism may obviously be secured in the usual wall .outlet box or any suitable container wherein such device/is desired.

The second adaptation incorporates` the invention in a receptacle designed for use with an attachment plug of. the polarized type. The

prongs of a'polarized plug are usually at right angles insteadof parallel to'each other. (If the prongs are merely of diiferent'shapes or sizes, the above-described mechanism may usually be employed.) the receptacle must, therefore, be similarly arranged. f

Referring nowto the drawings oi' the second adaptation of the invention:

Fig. '8 is aiview of a longitudinal section taken along the line v8---8 of Fig. 9;

Fig. 9 shows a transverse section' taken along line 9-9 ofthe complete receptacle of which Fig. 8 is a sectional view;

Fig.'V 10 is a sectional view similar to that` of Fig. 8 after a two-prong polarized attachment plug has been inserted -in the receptacle;

Fig. 11 is a sectional view taken at the line II-II ofFig.9; 1

Fig. l2 and Fig. 13 are views of opposite ends of the receptacle with the end cap removed.

Certain details of the mechanism are shown in Figs. 14-21 as follows:

Fig. 14 shows the mechanism at line I4-I4 of Fig. 9, and Fig. 15 is a similar viewarterV the prongs of an attachment plug have been inserted; l Fig. 16 shows the mechanism at line IS-IS of Fig. 9, and Fig. 17 is a similar view after the The receiving holes in the face of Y prongs of an attachment plug have been inserted;

28-20 of Fig. 9, and Fig. 21 is a similar view after the prongs of an attachment plug have been inserted.

vIn this group of gures the same reference characters represent the same parts; and reference characters which also appear in the figures of the other groups of drawings represent corresponding parts.

In this adaptation the holes in the face of the receptacle are placed at right angles, as shown at 3 and 4 in Fig. 13, to accommodate the prongs of the polarized plug. Here the door 1 serves to close the hole 3 which is turned at right angles to the door 8 serving to close hole L4, as shown in Figs. 8-11. Because of this arrangement the doors cannot be assembled in the back-to-back relation shown in the preceding figures, from which it follows that different locking means must be employed. As before, however. there are two locking means associated with each door, only one of which is released by the insertion oi' one of the prongs in its hole. Beneath the hole 4 door 8 is hinged on pin 36. This door is locked against opening by two dogs 48 and 43. Dog 40 is secured to shaft 34 which is rotated by pressure on releasing means or trip I8, and dog 43 is attached.to shaft 33 which is rotated by pressure on releasing means or trip 9. Therefore, when both prongs of the attachment plug are inserted in the holes 3 and 4, trips 9 and I0 are depressed.- shafts 33 and 34 are rotated, and dogs 43 and40 are swung away, from each other, allowing the heel of door 8 to move into the space which the dogs formerly occupied, thus .opening hole 4, and permitting access `to contact spring Ii. Door 1 is hinged on pin 46 which is at right angles to pin 36 for door 8. As before, this door is also locked by two separate locking means, one being actuated by the rotation of shaft 33 and the other by rotation of shaft 34. In this instance, however, the hinge pin 46 of the door is parallel' to the dogreleasing shafts 33 and 34 which requires` a dif- To this end, a' latch 38 is secured to shaft 34 bearing on a shoulferent type of locking means.

der at the rear of the door 1, as shown in' Fig. 18, preventing the door from swinging toward the latch `until the latch is turned away, as shown in Fig. 19. The `second locking means for door 1 is shown more clearly in Fig. 18 to comprise a pin 39 secured near the face of the door, and a swinging.' (toward the left in the figures), but is permitted to do so when strap 4I is turned awa as shown in Fig/'19. f Springs I3 and I4 are anchored at one end t anchor post 42, and at their other `ends are secured respectively in ears 45 and 44 attached to shafts 33and 34. By pulling on these. ears the springs tend to hold dogs 40 and 43 in closed position as shown in Figs. 8 and 9, the dogs in tuin tending to swing door 8 into its closed position. Likewise spring I4 tends to turn door 1 to its closed position by causing latch 38 to press against the back of that door.

Pin 31 serves to .retain one end of the shaft 34. the other end of the shaftbeingwretained by hinge inserted in a hole in shell l, andis retained near the other end by pin 63.

'I'he third adaptation of the invention will now be referred to in connection with theV remaining figures. It is useful either with the polarized or unpolar-ized type of attachment plug, but the drawingsillustrate a receptacle intended for use' with the unpolarized type such as illustrated in connection with the first adaptation. The third adaptation differs from the rst two mainly in that the safety doors'which close the prong-receiving holes are, in this instance, secured to or are an integral part of a single shding member. The door surfaces are therefore caused to close and open the respective holes by a sliding motion, rather than by a rotating one as described above.

Referring to the drawings:

Fig. 22 is a view of a longitudinal section taken along the hne 22-22 of Fig. 23;

Fig. 2 3 shows a transverse section taken along the line 23-23 of the complete receptacle of which Fig. 22 is a sectional View;

Fig. 24 is a sectional viewsimilar to that of Fig. 22 after an attachment plug has been inserted in the receptacle Fig. 25 is a sectional view takenl at hne 25-25 of Fig. 23;

Fig. 26 is a sectional view similar to that of Fig. 25 after an attachment plug has been inserted in the receptacle;

Fig. 27 "is a sectional view taken at line 21-21 of Fig.v 23; and

Aand 5.y However, upon insertion of an attachment plug 23, the connection prongs 25 and 26 press down the releasing means or trips 9 and I0, rotating shafts 51 and 56 respectively, and lifting latches 5l and 52 from locking holes 53 and 5d, respectively'. Thus, 'as the connection prongs of the plug are inserted further into holes 4 and 3,

they press against the cam-like door surfaces 48 and 49 and displace the slide member against the `spring 50, effectively opening the doors by aligning hole et mane slide witnhole e and by displacing the edge 65 of the `slide beyond the hole 3, thus allowing the connectionprongs to be inserted'ln contact springs 6 and 5.

Upon withdrawing the connection prongs of the. attachment plug the reverse operation 'takes place, that is, as the ends ofthe prongs are drawn away from the door faces 48 and 4 9, spring 59 closes the doors by moving slide member 41 to its original position. i

From` Fig. 23 it will be seen `that retaining v plates 59 and 60 hold slide member 41 in operative position. By removing these vplates slide 41 may be lifted out of its slideway. Shafts and 51 are held in place by bearing blocks 62 and 5l respec- I tively. When shafts 5B and 51 are rotated as the result of pressure upon trips IU and 9, they arerotated against the action of springs 58 and 55, respectively. These springs encircle their respective shafts under tension, one end. of each being secured to its shaft, and the other end being anchored to the corresponding bearing block as shown for example, in Figs. 23 and 27.

n From the foregoingdescriptlon of the mechal neither door can be moved to allow access to a contact spring or other live part of the receptacle until both releasing means 9 and I0 have been actuated. This is true because each of latches 5l and 52 serves to lock slide 41 in the closed position, and hence to lock both doors in closed position.

From the foregoing description of three adaptations of the present invention, those skilled in the art will understand how to modify the constructional details for various other adaptations. For example, three-wire cords and cables are frequently met with in practice, and require, of course, three-prong attachment plugs and threecontact receptacles. These are, in practically all cases, polarized so that the attachment-plug prongs can be inserted into the receptacle only in one way. lIf the. third wire is grounded (as is frequently the case) it is not always necessary that a safety door be provided for the third hole of the receptacle because there would then be no potential difference between the grounded wire and any grounded object. 1n that event, therefore, safety doors can .be provided for the other two holes of the receptacle according to any of the arrangements above described. If, however,

it is desirable to provide a safety door for the third hole in the receptacle it can readily be added in any appropriate manner depending upon its physical position with respect to the other holes. The exact mechanical layout for the doors, the locks, and the lock-releasing means would then depend largely upon the angles between the various holes in the receptacle. However, the forenism of Figs. 22-28, it is apparent that, like that of the other two adaptations above described,

going descriptions and drawings relating to mechi anism adapted to receptacles having yholes parallel and also holes at right angles to each other is sucient to enable a worker in the art to apply the invention .to receptacles having any number of holes and having holes at different angles. If there are an even number of holes it is usually convenient to arrange them, in pairs following the designs above described. `If there are an odd number of holes, there may still be releasing means associated witheach hole, but these releasing means may conveniently be arranged toA control a locking means on the door associated with the same hole simultaneously with the lockingmeanson the door associated with an adjacent hole, and so on in seriatim, until the releasing means at the last hole controls the locking means associated withA the door of that hole andv the door of the first-named hole.

In any event, the receptacle should be provided with a safety door to close each hole beneath which there is a live contact, and, as a minimum requirement, each such door should be locked fby at least one locking means which is released by a tripassociatedwith another hole, i. e., /the door andv the trip which, serves to release it' should not be associated with thev same prong-receiving hole. However, it is preferable to provide eachdoor with vat least two locking means, as above described in connection with three adaptations of the preferred embodiment of the invention.

What'is claimed is:

1. In an electric receptacle having a plurality. of holes adapted to receive the connection prongs l of an attahmentfplug, a door portion and a trip associated with each hole, said door portion bethere are prong-receiving holes in said receptacle,

ing provided with as many locking means `as spring-closed door for each hole, at least twov locking .means associated with each door, any one of which serves to hold said door closed,and releasing means associated with each hole operated by the insertion of a connection prong therein to release only one of the locking means simultaneously for each door.

3. An electric receptacle which comprises a housing,l electrically charged terminals secured within said housing, said housing having holesl in a wall thereof in alignment with said electrically charged terminals through which the prongs of a connection plug may be inserted to engage said electrically charged terminals, and means in the housing operable to shield said terminals from contact through the openings, said means including a movable door interposed between each terminal and the hole leading thereto and normally closing the hole, a locking device for each door operable to hold the door in closed position, and trips `in the housing, each trip having a portion exposed-'in one of the holes for engagement and operation. by a connection prong when inserted through said opening, each trip being operable to render inoperative the locking device for'a door closing an opening different from that in which said trip is exposed.

4. An electric receptacle which comprises a housing, electrically charged terminals secured within said. housing, said housing halve holes in a wall thereof `in alignment with said electrically charged terminals throughwhich the prongs of a connection plug-may be inserted to engage said electrically charged terminals, and means in the housing operable to shield the terminals from contact through the holes, said means including a movable door interposed between each terminal and the hole leading thereto and normally closing the hole, a plurality of locking devices, the same in number as the doors, each device bean opening for engagement and operation by a connection prong when inserted through said opening, each 'trip` being operable to render a locking device inoperative..

5. An electric receptacle which comprises a housing, electrically charged spring terminals' secured within 'said housing, said housing having .holes in a wallv thereof in alignment with said in a single direction towards said spring terminals, two locking `means associated with each door, each ofwhich serves to hold said door closed, and releasing means associated with each hole for operation by the insertion of a connection prong therein to release one of said two locking means simultaneously for each of said doors, thereby to permit said connection prongs toengage said spring terminals.

6. An electric receptacle provided with an insulating portion forming at least two spaced holes adapted to receive a like number of connection prongs of an attachment plug, a spring-closed door for each of said two holes hinged between said holes in spaced relation, each door having a surface which effectively opens said hole by swinging away therefrom, and a portion which swings into the space between said doors, locking dogs positioned in said space, each of which serves to prevent both of said doors from swinging, and a trip associated-with each of said two holes, each trip being attached to a different one of said dogs and being operated `by the insertion of a connection prong in its respective hole to move the dog to which said trip is attached, whereby the insertion of connection prongs in both of said holes releases both ofsai'd doors to open.

7. An electric receptacle provided with an insulating portion forming two rectangular oblong holes spaced with their long axes at right angles to each other and adapted to receive the connection prongs ofa polarized attachment plug, a

spring-closed door for each-hole hinged substani tially parallel to the long axis of the hole with which it is associated, each door having a surface'which effectively opens said hole by swinging away therefrom, a trip associated with each of said holes, two shafts, one attached to each trip, each trip being operated by the insertion of a connection prong in its respective hole to rotate the shaft to which said trip is attached, a dog and a latch being secured to one shaft and a dog and a locking strapv being secured to the other shaft, both of said dogs being operative to lock and release one of said doors, and said latch and said strap being operative, in cooperation with a shoulder and a pin positioned, respectively,

on opposite sides of the other of said doors, to

lock and release said last-named door.

8. In an electric receptacle, an insulating portion forming at least two holes adapted to receive the connection prongs of an attachment plug, a slide member having portions effective to close said holes and cam-like surfaces cooperating withsaid connection prongs tovdisplace said slide member thereby effectively to open said holes, at least two locking means serving to lock said slide member in closed position, and separate releasing means for said locking means, one associated with each of said holes, said releasing means being operated by the insertion of said connection prongs in said holes to release said locking means 9. In an electric receptacle, an insulating portion forming two holes adapted to receive thel connection .prongs of an attachment plug, a slide member of insulating material ,having portions tion prongs to displace said slide member thereby effectively to open -said holes, two locking means serving to lock said slide member in closed position, and separate releasing means for said locking means, one associated with each of said holes, each of said releasing means being attached to a different one of said locking means and being operated by the insertion of said connection prongs in said holes vrespectively to release said lockingmeans.

l0. An electric receptacle provided with an insulating portion forming twoholes adapted to receive the connection prongs of an attachment plug, ycontact springs positioned in alignment with said holes, a spring-closed slide member secured beneath said holes having cam-like door surfaces effectively closing saidholes, two locking holes in said slide member and .two latches coarenoso whereby said'prong-receiving holes are opened to" permit said prongs to engage said contact springs.

l1. An electric receptacle which comprises a housing, electrically charged spring terminals secured within said housing, said housing having holes in the wall thereof in alignment with said spring terminals through which the prongs of a connection plug may be inserted to engage said spring terminals, a spring closed door i'or each hole having a cam-like face displaceable by pressure exerted by a connection prong moving in the direction of insertion, a plurality of independent locking means associated with each door serving to hold each door closed, and releasing means associated with each hole operated by insertion therein oi' a connection prong to release one of said plurality of locking means simultai'ieoush for each of said doors, thereby to permit said connection prongs to displace said doors and to engage said terminals by continued insertion in the same direction.

12. Anv electric receptacle which comprises a housing, electrically charged terminals within said housing, said housing having a plurality of holes in a wall thereof through which the prongs of a connection plug may be inserted to engage said electrically charged terminals, a door portionand a trip associated with each hole,y each door portion being provided with at least one locking means serving to loclr said door portion in a position effectively closing the hole with which it is associated, and means operatively connecting the locking means which locks the door portion associated'with each one of said holes with the trip associated with another-of said holes, whereby insertion oi a connection prong in any one hole actuates the trip associated withfthat hole and releases the locking means associated with another hole. 

